Stabilization of hydrocarbon oil heavier than gasoline



United States Patent STABILIZATION F HYDROCARBON OIL HEAVIER THAN GASOLINE Joseph A. Chenicek, Bensenville, Ill., assignor, by mesne assignments, to Universal Oil Products Company, Des Plaines, 111., a corporation of Delaware No Drawing. Application September 19, 1955 Serial No. 535,286

6 Claims. (CI. 44-63) This application is a continuation-in-part of copending application Serial No. 238,008, filed July 21, 1951, and now abandoned, and relates to the stabilization of hydrocarbon oil heavier than gasoline, and more particularly to the use of a novel additive in retarding and/ or preventing deterioration of such hydrocarbon oils in storage.

The invention is particularly applicable to the stabilization of burner oils which undergo discoloration and form undesirable sediment in storage. Burner oils are marketed under various trade names such as fuel oil, furnace oil, burner oil, diesel fuel, jet fuel, etc. and are selected to meet commercial specifications. It is understood that the term burner oil is used in the present specification and claims in a generic sense to include hydrocarbon distillates heavier than gasoline. In general, these hydrocarbon distillates will have initial boiling points ranging as low as 300 F. and end boiling points which may range up to about 750 F.

Discoloration of burner oil is undesirable because marketing of the burner oil in most cases includes a color specification, and, therefore, it is important that the burner oil does not undergo discoloration in storage. Similarly, the formation of sediment in burner oil is objectionable because the sediment tends to plug strainers, burner tips, injectors, etc., and when used as diesel fuel, tends to form varnish and sludge in the cylinders of the diesel engine. The sediment referred to herein is different from the solid material originally contained as such in burner oil and referred to in the art as B.S. & W. The sediment with which the present invention is concerned is not contained in the burner oil as produced but forms during storage.

At the present time burner oils come primarily from non-destructive distillation of petroleum oil, commercially referred to in the art as straight-run distillates, and from catalytic and non-catalytic cracking processes, commonly referred to in the art as cycle stocks. The term cycle stocks is used because the burner oil is separated from a fraction which is otherwise recycled to the cracking process for further conversion therein. Other sources of burner oil may include those produced by the reaction of carbon monoxide with hydrogen, etc. Regardless of the source, many of the burner oils are unstable in storage and undergo discoloration and sediment formation. This is particularly true in blends of straight run petroleum distillates and cracked hydrocarbon oils, particularly catalytically cracked hydrocarbon oils, all being heavier than gasoline. Because of the increased amount of cycle stocks available, many refiners are marketing blended burner oils and, therefore, require some method of retarding and/ or preventing this undesirable deterioration.

In one embodiment the present invention relates to a process for stabilizing hydrocarbon oil heavier than gasoline against deterioration in storage which comprises adding thereto a 1,3-diazine having an amino substituent attached to the 2 carbon atom.

In a specific embodiment the present invention relates to a process for retarding discoloration of burner oil in 2,888,331 Patented May 26, 1959 lates to hydrocarbon oil heavier than gasoline tending to deteriorate in storage, and particularly burner oil, containing, as a retardant of said deterioration, a minor amount of the additive herein set forth.

In the interest of simplicity, the following specifications will be directed primarily to the treatment of burner oil. However, it is understood that the invention is applicable to the treatment of other hydrocarrbon oils heavier than gasoline including jet fuel, mineral oil, lubricating oil, etc.

In accordance with the present invention, deterioration of hydrocarbon oil heavier than gasoline is retarded by adding thereto a 1,3-diazine having an amino substituent attached to the 2 carbon atom, and more particularly a hydro-1,3-diazine having an amino group attached to the 2 carbon atom including a 2-alkylamino-4,S-dihydro- 1,3- diazine, a Z-amino-1,4,5,6-tetrahydro-1,3-diazine and a 2- amino-hexahydro-1,3-diazine.

The particular 1,3-diazines for use in the present invention are illustrated by the following general structures.

Structure I illustrates a 1,3-diazine and R may be selected from the group comprising hydrogen, hydrocarbon groups including alkyl, aralkyl, aryl, arkaryl, alkenyl, cycloalkenyl, cycloalkyl, amino, guanylamino,

7 nitro, nitrohydrocarbon, hydroxy, hydroxyhydrocarbon,

etc. Specific compounds of this structure include 2-amino pyrimidine, Z-amino- 4,5,6-tributyl pyrimidine, 2,4,6-triamino-S-hexyl pyrimidine, 2-amino-4,4,6-trimethyl pyrimidine, Z-ethylhexylamino 4,4,6-trimethyl pyrimidine, 2- dodecylphenylarnino-4,4,6-trirnethyl pyrimidine, etc.

The hydro-1,3-diazines are preferred and particularly the 4,5-dihydro-1,3-diazines illustrated in structure II. Here again, R may be selected from the group hereinbefore set forth. Specific compounds of this structure include 2-amino-4,5-dihydropyrimidine, 2,4-diamino-4,5-dihydropyrimidine, 2,6-diamino 4,5 dihydropyrimidine, 2,4,6-triamino-4,5-dihydropyrimidine, 2-(3 phenylguanylamino)-4,4,6-trimethyl-4,S-dihydropyrimidine, 2 (2- ethylhexyiarnino) 4,4,6 trimethyl 4,5 dihydropyrimidine, 2-(2-dodecylphenylamino)-4,4,6-trimethyl-4,5 dihydropyrimidine, 2-amino-4-hydroXy-6-octyl-4,5 dihydropyrirm'dine, etc.

Structure III illustrates a l,4,5,6-tetrahydro-1,3-diazine, wherein R may be selected from the group as hereinbefore set forth. Generally it is preferred that the numbering of this compound be 1,2,3,4-tetrahydropyrimidine. However, in the interest of uniformity in illustrating the structure, it has been decided to number the compounds of structure III as 1,4,5,6-tetrahydropyrimidine. Suitable compounds of this structure include 2-amino-1,4,5,6-tetrahydropyrimidine, 2,4-diamino-1,4,5,6 tetrahydropyrimidine, 2,4,6 triamino-l,4,5,6 tetrahydropyrimidine, 2- amino-4,4,6-trimethyl 1,4,5,6 tetrahydropyrimidine, 2- amino-4-hexyl-6-hexylamino 1,4,5,6 tetrahydropyrimidine, 2-dodecylphenylamino-4-propyl-6-amino 1,4,5,6- tetrahydropyrimidine, 2-(3-phenylguanylamino)-4,4,6-trimethyl-1,4,5,6-tetrahydropyrimidine, 2 (2 ethylhexylamino)-6-amino-1,4,5,6-tetrahydropyrimidine, etc. It is understood that the tetrahydro structure may comprise the 1,2,5,6-tetrahydropyrimidine structure and include such compounds as 2-amino-4-propy1-6-dodecylphenylamino-1,2,5,6-tetrahydropyrimidine, 2-amino-4-methyl-6- (3-phenylguanylamino) l,2,5,6 tetrahydropyrimidine, etc.

Structure IV illustrates a hexahydro-1,3-diazine and here again the R group may be selected in the manner as hereinbefore set forth. Representative compounds of this structure include Z-amino-hexahydropyrimidine, 2,4- diamino-hexahydropyrimidine, 2,4,6-triamino-hexahydropyrimidine, 2-amino-4-propyl-6-dodecylamino-hexahydropyrimidine, 2-(3-phenylguanylamino) 4,4,6 trimethylhexahydropyrimidine, 2-(2-ethylhexylamino) 4,4,6 trimethyl-hexahydropyrimidine, 2-amino-4-dodecylphenyl-6- hydroxyhexahydropyrimidine, etc.

It is understood that the carbon atoms in positions 5 and 6 may comprise carbon atoms of a cylic compound and the substituted pyrimidine then will comprise a bicyclic compound. For example, referring to structure 'I, when carbon atoms in the 5 and 6 positions also comprise a portion of an aromatic ring, the additive will comprise a quinazoline, or if a portion of a S-membered heterocyclic ring containing 2 nitrogen atoms, the additive will comprise purine.

It is understood that the additive of the present invention may comprise the specific compounds named herein alone or in admixture with various isomers thereof. Furthermore, it is understood that the various additives which may be utilized in accordance with the present invention are not necessarily equivalent for use in the stabilization of the different hydrocarbon'oils heavier than gasoline which may be treated in accordance with the present invention. Furthermore, it is understood that the particular additive to be used should be selected so as to meet the specific requirements of the particular material being stabilized. For example, in the treatment of burner oil, the R groups should be selected so that the additive contains a total of from about 10 to about 30 carbon atoms per molecule in order that the additive will not be too volatile, will be readily soluble, etc. It is appreciated that the particular selection of the substituent groups will depend upon the particular hydrocarbon oil heavier than gasoline in which the additive is to be employed.

The 1,3-diazines of the present invention may be prepared in any suitable manner. 2-alkylguanylamino-4,6- dimethyl-pyrimidine may be prepared by the condensation of an alkyl bigdlanide with acetylacetone. Z-guanylamino-4-methyl-fi-hydroxy-pyrimidine may be prepared by the reaction of biguanide with ethylacetoacetate. Diaminopyrimidines are obtained by the reaction of guanidine with alpha-cyano-acetates. Triaminopyrimidines are obtained by the reaction of biguanide with malononitriles. Dihydropyrimidines may be prepared by the reaction of guanidines or bignanides with mesityl oxide.

The additive of the present invention is generally added to the hydrocarbon oil heavier than gasoline in an amount of less than about 1% by Weight and more generally within the range of from about 0.000l% to about 1% and preferably of from about 0.001% to about 0.1% by weight. It is understood that these additives may be used alone or in conjunction with other additives employed for specific purposes depending upon the particular oil being treated. For example, in the treatment of burner oil, these additives may be used in conjunction with antioxidants which may comprise aliphatic amines, amino alcohols, imidazolines, etc., metal deactivators, dyes, detergents, drying agents, etc.

In most cases, the additives of the present invention will be liquid at atmospheric conditions and, therefore, may be readily incorporated in the oil to be stabilized. When desired, the additive may be utilized in a suitable solvent, including hydrocarbons, alcohols, glycols, ethers, ketones, etc., and in such cases, the additive may be prepared as a solution in the solvent and marketed in this manner alone or along with any other component to be included in the mixture as hereinbefore set forth.

The following examples are introduced to illustrate further the novelty and utility of the present invention but not with the intention of unduly limiting the same.

EXAMPLE I This example illustrates the beneficial elfects of 2-(3- phenylguanylamino)-4,4,6-trimethyl-4,5 dihydropyrimidine in retarding discoloration of a burner oil. This additive was prepared by the reaction of phenyl biguanide with acetylacetone in the manner hereinbefore set forth.

Discoloration of the burner oil containing various additives was determined in an accelerated test, which avoids the necessity of running long time storage tests in order to determine the effect of the various additives. In other runs it has been found that this accelerated test correlates quite satisfactorily with the long time storage test and, therefore, gives a true picture of the stability of the fuel. The samples of the fuel oil were stored at C. for 20 hours. The color was determined in a Lumitron, Model 402-E, Spectrophotometer, and the data are reported as the percent transmittance. It is apparent that the percent transmittance is inversely proportional to discoloration, and that high percent transmittance means low discoloration.

2 (3 phenylguanylamino) 4,4,6 trimethyl 4,5- dihydropyrimidine was added in an amount of 0.006% by weight to a sample of the burner oil. This sample, together with a sample not containing the additive, was tested in the accelerated test described above. The results are shown in the following table:

Table I Additive Percent Transmittance None- 2-(3-phenylguanylamino)-4,4,6 trimethyl 4,5 dihydropyrimidine It will be noted that the sample not containing the additive became very dark in color after aging at 100 C. for 20 hours. On the other hand, the sample containing the 4,5-dihydropyrimidine still had a percent transmittance of 68 after aging in the same manner.

EXAMPLE H a EXAMPLE III This example illustrates the beneficial effects obtained by the use of the additive of the present invention in reducing sediment formation in burner oil. The burner oil used in this example was the same as that described in Example I. The sediment was determined by filtering a sample of the oil after exposure to light from a carbon are for 90 minutes under controlled conditions. This accelerated test has been found indicative of relative storage stability.

0.01% by weight of the additive was added to one sample of the burner oil and, after testing in the manner described herein, the sample containing additive and a sample without additive had the following sediment content:

Table II Sediment, Additive mg. per

None. 3. 1 2-{g-phenylguanylamino)-4,4,6-trimethyl4,5-dihydropyrimdiazine having an amino substituent attached to the 2 carbon atom, said diazine consisting of carbon, hydrogen and nitrogen.

3. Hydrocarbon oil heavier than gasoline normally subject to deterioration in storage containing, in sulficient amount to retard said deterioration, a dihydro-l,3- diazine having an amino substituent attached to the 2 carbon atom, said diazine consisting of carbon, hydrogen and nitrogen.

4. Hydrocarbon oil heavier than gasoline normally subject to deterioration in storage containing, in sulficient amount to retard said deterioration, a tetrahydro- 1,3-diazine having an amino substituent attached to the 2 carbon atom, said diazine consisting of carbon, hydrogen and nitrogen.

5. Hydrocarbon oil heavier than gasoline normally subject to deterioration in storage containing, in sufificient amount to retard said deterioration, a hexahydro- 1,3-diazine having an amino substituent attached to the 2 carbon atom, said diazine consisting of carbon, hydrogen and nitrogen.

6. A hydrocarbon burner oil heavier than gasoline and normally subject to deterioration by discoloration and sediment formation in storage containing, in sufiicient amount to retard said deterioration, 2-(2-ethylhexylamino) -4,4,6-trimethyl-4,S-dihydropyrimidine.

References Cited in the file of this patent UNITED STATES PATENTS 2,553,183 Caron et al. May 15, 1951 2,622,018 White et a1. Dec. 16, 1952 2,734,814 Thomas Feb. 14, 1956 2,754,183 Chenicek et al. July 10, 1956 

1. HYDROCARBON OIL HEAVIER THAN GASOLINE NORMALLY SUBJECT TO DETERIORATION IN STORAGE CONTAINING, IN SUFFICIENT AMOUNT TO RETARD SAID DETERIORATION, A 1,3-DIAZINE HAVING AN AMINO SUBSTITUENT ATTACHED TO THE 2 CARBON ATOMS, SAID DIAZINE CONSISTING OF CARBON, HYDROGEN AND NITROGEN. 